Materials Science Forum Vols. 537-538

Abstract: The purpose of this work is the development of microcoulometric cell for measurement of halogenide ions in the range of ng amounts. The main task in the innovation is to fulfil the need of sensitive halogene determination in the automated measurement of the so-called adsorbable organically bound halogens (AOX) in waters. The very low consumption of supporting electrolyte and the energy saving configuration is also important factors in designing of monitor operation. We developed a micro volume tube reactor, which can work continuously with peristaltic pumps feeding the supporting electrolyte and the sample. The tube cell allows the injection of liquid and gas samples without changing the cell construction. A three electrode type potentiostatic microcoulometer with a rotating Ag working electrode was built, which maintains a constant electrode potential of the working electrode to the reference electrode by the generation of silver ions through anodic dissolution. The halogenide ions in sample solution change the electrode potential of the working electrode. The potentiostatic controller circuit sets a current flowing between the Ag working (anode) and a counter electrode (cathode). This current generates silver ions from the working electrode, these ions precipitate the halogenide ions from the cell electrolyte and restore the potential of the working electrode. It was a further successful hydraulic development to achieve a microvolume cell, which accepts both gas and liquid samples in the same equipment. The developed microcoulometer system has high sensitivity and works reliable in a wide measuring range.

Abstract: Miniature structures can be produced economically by micro end milling as single parts or parts in small and medium lot sizes. The micro end milling process has to be analyzed particularly for the purpose of applying a well controlled and repeatable process. There are many specific characteristics in the micrometric scale of dimensions, whose role is negligible at the conventional processing technologies. One of these special features of micro end milling is the observation that the set value of the feed rate per tooth generally differs from the thickness of the actual removed material layer. Feed rate per tooth is practically defined as the distance, which is run by the edge lengthwise of the groove during one revolution of the tool. Accordingly the feed rate per tooth corresponds to the thickness of the material layer removed by one edge of the tool. This correspondence exists at conventional manufacturing methods but not at micro end milling. This fact is attended by more special features of the micro end milling process, which are multiple cutting, different machining conditions of the edges and tool deflection. This paper introduces the results of improvement of my earlier research on this field [1]. An enhanced flowchart was constructed, which provides the calculation of the thickness of the actual removed material layer at micro end milling under all possible circumstances.

Abstract: Analysing the function of steel scrap and understanding its influence on development, are the main problems which interests the steel producers of the world. To create such an essay, the analysis of the actual developments of the quantities, the qualities and compositions of the used scrap types should be continuously monitored in the world’s steel industry. Series of local experiments and evaluating statistics focusing on process optimization by scrap have been done at ThyssenKrupp Steel. This includes the current study based on the records of scrap charges. In the following paper the development of an indirect scrap evaluation algorithm will be discussed, compared with results of the common ways.

Abstract: The paper summarises the results of our investigations on the conductive silicone rubber as strain sensor. The dynamic behaviour of silicone rubber shows strong nonlinearity and because of the relaxation and creep the sensor can not be used for static measure. The greatest advantage of this material lies in its high elasticity. The commercial strain metallic or semiconductor gauges work in the range of 10-7<ε<10-3 . With the new silicone rubber sensor one can achieve elongations typically in the range of 10-2<ε<102 so this sensor offers new possibilities for the measure and control of high elasticity structures. The fatigue tests show that dynamic behaviour of the sensor silicone is stable.